Polylactic acid resin composition

A polylactic acid resin composition comprising:

• a polylactic acid resin comprising a hard segment comprising a polylactic acid repeating unit of Formula 1 and a soft segment comprising a polyolefin-based polyol repeating unit in which polyolefin-based polyol structural units of Formula 2 are linked in a linear or branched manner via a urethane bond, wherein the organic carbon content (% Cbio) of biomass-based carbon, as defined in Equation 1, is at least 60 wt %, wherein, in Formulae 1 and 2, n is an integer from 700 to 5,000, and m+1 is an integer from 5 to 200;
• and
• an antioxidant:
• % Cbio=(weight ratio of 14C isotope to 12C of the total carbon content in the polylactic acid resin)/(weight ratio of 14C isotope to 12C of the total carbon content in a biomass-based carbon standard material), wherein the antioxidant is used in an amount of 100 to 3,000 ppmw based on the amount of the monomers for forming the polylactic acid repeating unit, and [Equation 1]
• wherein the polylactic acid resin is prepared by reacting an isocyanate containing compound with polyolefin-based polyol structural units of Formula 2 to form the soft segments, and then reacting the soft segments with the polylactic acid repeating units of Formula 1.